The optical communication experiment is a very exciting piggyback, but it's disappointing that the press release is 95% background on the Psyche missing and only a tiny blurb about that experiment. Where are the receivers? How far away do they expect to be able to pick up communication? How do they get the angle of the laser to the incredible accuracy they need?
Not only do they have to point very accurately, both terminals will have to simultaneously point at where the opposite terminal was (for receiving) and will be (for transmitting) because of the light time delay. The distances will be so vast and so little light will arrive at Palomar that they will have to employ a superconducting (cooled to a fraction of a Kelvin) nanowire single photon detector. The modulation format is orders of magnitude more efficient (from an energy per bit perspective) than Kuiper or Starlink even though the data rate is (necessarily) lower.
Artemis II is scheduled to use the same modulation format and could use the same uplink and downlink terminals. JPL is building a "hybrid" Ka/X-band/optical terminal in the desert in Goldstone that may be able to let Palomar spend more time on astronomy.
Do you have specs on the starlink or kuiper laser terminals? SpaceX has been hush hush about the former and I didn’t even think kuiper had anything for laser comms yet.
This system probably isn't very comparable to the Starlink space lasers. Because of scale, Starlink is very heavily optimized for cost, while a bespoke deep space terminal probably doesn't even have cost as a factor.
It's one thing building (a pair of) working optical communications terminals. Designing it so you can build tens of thousands of them is a totally different game.
> Optical to Orion (O2O) is a plan to do a lasercomm demo on one of the future Orion moon missions.
> When the Psyche spacecraft launches and heads to the asteroid belt (was supposed to launch in august) it will do the farthest (by far) lasercomm demo. I work in the group that made the SNSPD ground receiver. As my boss says, with a distance 1000x farther than previous space laser comm demos, closing the link is 1 million times harder...
> Fun fact: when the Phyche comm laser is pointed at earth, the size of the spot will be roughly as large as California. Even with the largest optical telescopes, the loss in this link will be insane. That's why you need single photon detectors.
> As you get to farther and father distances, one thing you can do is shift from on/off keying to large-M Pulse Position Modulation. This way you can save up the power on your satellite to send fewer but higher power laser pulses, each of which carries more bits of data. I believe the DSOC mission will go up to M=256. Meaning each pulse of photons received on earth will carry 8 bits of information based on when it arrives within an alphabet of 256 time bins.
They are using ground based telescope observatories. "...To receive the downlinked high-rate data sent from the probe, NASA is relying on the 200-inch Hale Telescope at Caltech’s Palomar Observatory in San Diego County, which sits atop a mountain south of JPL."
The sonic boom crack is really cool. I didn’t realize it goes trans-sonic at such low altitude but it makes sense given how much thrust the F9 has and the low weight of the empty booster.
This is a really exciting mission, imho - probably one of the most exciting of all current space missions.
The reason is that 16 Psyche is hypothesized to be a very, very rich ball of metal. A million times the material wealth we have here on Earth, in fact. More gold, silver, platinum, iron, zinc, etc. than we can even fathom exists, accessible on our surface here on Earth.
If we arrive and find it full of gold and other valuable metals, I'd imagine the following 10 years afterwards, humans are going to be on a race to get there, set up shop, and start 3D-printing Starships.
Its far-fetched and fantastic, but I could imagine a scenario where this race really takes off. 10 years from now, we might very well have the technology to exploit this gigantic ball of materials in super interesting ways. (Assuming we don't nuke ourselves into oblivion, obviously. Lets just put that aside.)
Imagine, we start moving heavy-metal industries to space. 3D Printers set up shop on the 16 Psyche surface, and starts churning out Starships (which by then should be perfected for human-rated travel around our star system, hopefully).
One can dream. I sure hope I'm alive to see the first pictures of arrival.
Gold as a store of value would probably be worse off than bitcoin in this case but personally I hope it's either that or copper - would mean a lot for world electrification.
It would affect the market for gold as a store of value, certainly. But for actual useful economic purposes, the cost of getting those metals back to the surface of the Earth would be so eye-wateringly expensive that I don't know if it would even make sense.
A single SpaceX Starship claims to have a reusable payload of 150 tons. Current annual mining operations extract 21 million tons of copper, 3,000 tons of gold, and 300 tons of platinum. So let's focus on platinum. You'd need two starships per year to match current platinum production. But it's a 12-year round trip, so you'd need 24 starships in continuous operation just to haul the metals (let's ignore where they're getting their fuel from for the return trip). And that's before you get to the actual costs of the mining operation itself; bootstrapping fully autonomous robotic space mining on a rock 200 million miles away is going to take more money that anyone has lying around. And the final result of this is that you've spent a trillion dollars just to crash the market for platinum.
You need to consider the costs associated with in-orbit mining and then de-orbiting the material before declaring terrestrial mining dead. Those are big unknowns at the moment.
It might only be useful for in-orbit manufacturing, which is also a near complete unknown at this point. Pretty exciting for anybody contemplating building massive orbital stations.
> “I am excited to see the treasure trove of science Psyche will unlock as NASA’s first mission to a metal world,” said Nicola Fox, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “By studying asteroid Psyche, we hope to better understand our universe and our place in it, especially regarding the mysterious and impossible-to-reach metal core of our own home planet, Earth.”
Why call a metal world 'psyche'? (Where psyche is the Greek word for heart.)
As far as I know, Psyche was named before its metallicity was known (it’s only the 16th asteroid ever discovered!) but the name is surprisingly apt given how it was long thought to be the exposed core of a protoplanet. The hypothesis appears to be mostly ruled out by observations, though.
I don't know why I find it interesting but Psyche asteroid is 31 minutes and 33 light seconds from Earth. Assuming my math is correct, at 400 Mbps, there would be roughly 94 GB of data "in flight" through space between the satellite and the Earth.
> I didn't detect it coming. I first noticed it on a webcam feed, of all places. It must have come out of an observational blind spot. Solar glare alone cuts out a quarter of the sky, to say nothing of our enormous coverage shortfalls, but now's not the time for retrospectives.
After reading the story it makes me think of a quote from a Bujold book, where one fantasy character talks about how it was a godly miracle that 300 heathen invaders were completely eradicated after their grave sin of murdering one local saint, and another character retorts.
Adjusting that response to fit:
"I would be considerably more impressed with your global nanotech overlord AI," said Ista through her teeth, "if He could have arranged a few satellites worth of simple detection in advance, rather than several billion lives' worth of gaudy evacuation afterward."
It's definitely an interesting way of thinking about it. It makes the "how much data is currently in the queue" question much more interesting.
However, most of that data will be redundant. "Hi! I'm still here! I'm currently at blahblahblah position, and my status is nominal" over and over and over
What do you consider "in flight"? There's an old joke from Tanenbaum: "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
And while it was very much not a high-capacity technique, you might find the mercury delay-line memory used by early computers interesting if you haven't heard of it before.
